Genetic Study Points to Bats as Source of Marburg Disease

More than half of those infected in a two-year outbreak in Africa worked in a gold mine where the animals were present, a report finds.

The most extensive genetic study conducted on an outbreak of lethal Marburg disease in Africa adds to evidence that the disease is linked to caves and possibly the bats that live there.

People from two villages unwittingly carried the virus from the gold mine where they worked to their homes, said Robert Swanepoel, a South African epidemiologist and co-author of the study in the current issue of the New England Journal of Medicine.

The outbreak occurred in the Democratic Republic of Congo from 1998 to 2000.

The two-year outbreak of the disease, which causes internal organs to bleed uncontrollably, killed at least 125 people.

More than half of the cases occurred in young men who worked in the gold mine, the study said.

Genetic tests showed that at least nine strains of the virus were involved in the outbreak, suggesting that the men contracted the disease in the caves and did not transmit it among themselves.

Swanepoel said he thought bats played a crucial role, perhaps transmitting the virus in their droppings.

"We haven't solved it yet," he said. "The evidence for bats is quite strong, but it still isn't cast iron."

Scientists want to know which species carries the virus without getting sick itself, allowing the disease to remain in the environment.

"It's extremely important to find the animal reservoir of the virus," said Heinz Feldmann of the Public Health Agency of Canada, who wrote an accompanying editorial in the journal. "That's a way to start prevention, education and other countermeasures that can keep people from getting the disease."